<template>
  <div>
    <h3>{{ num }}</h3>
    <!-- <TestNum :numSon="num" @update:numSon="num = $event"></TestNum> -->
    <!-- <TestNum :numSon.sync="num"></TestNum> -->
  </div>
</template>
<script>
export default {
  data () {
    return {
      num: 0
    }
  },
  created () {}
}
</script>
<style></style>
